|AIKEN G E|
|SPRINGER T L|
Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/1995
Publication Date: N/A
Interpretive Summary: Switchgrass is a warm-season, perennial grass that has potential as a forage and alternative energy crop, but inconsistent establishment has limited its commercial use. A study was conducted to determine the effect of seed size on the germination of six different cultivars of switchgrass ('Alamo', 'Blackwell', 'Cave-in-Rock', 'Kanlow', 'Pathfinder', and 'Trailblazer'), and to determine if seed size interacts with planting depth and soil type in affecting emergence of each cultivar. There were substantial increases in germination as seed size increased. Larger seed showed higher emergence percentage, particularly in the sand; however, overall emergence was generally poor in both silt loam soils. There was no effect of planting between .2 and .8 inch depths for oil seed sizes. Thus, seed size appears to be more of a factor than planting depth in affecting emergence. Results of the studies could be important to the seed industry because they indicate that the consistency of establishing switchgrass could be improved through either breeding for larger seeded cultivars or by cleaning the seed to increase the proportion of larger seed. Establishment could further be improved if planted in lighter textured soils.
Technical Abstract: Switchgrass (Panicum virgatum L.) has potential as a forage and biomass crop, but difficult establishment has limited its use. Germination and emergence was studied for six different cultivars of switchgrass ('Alamo', 'Blackwell', 'Cave-in-Rock', 'Kanlow', 'Pathfinder', and 'Trailblazer'). Germination studies were conducted to determine the effect of light on germination and coleoptile length, and to determine the effect of seed size (40, 50, 60, 70, and 80 degrees air valve settings for a South Dakota seed blower) on germination. A greenhouse study was conducted also to determine the effect of seed size, planting depth, (5, 10, and 20 mm), and soil type (sand and two silt loams) on emergence. Germination of unsized seed increased linearly (P<0.05) as duration in the germination chamber increased from 7 to 21 days for all cultivars. Although presence of light did not affect germination, coleoptile lengths under continuous darkness averaged 4.1 cm and was greater than the 1.0 cm for those with daily light exposure of 8 h (P<0.001). Germination and emergence both increased curvilinearly as seed size increased (P<0.05). For both silt-loam soils, emergence was low and not affected by planting depth. Curvilinear declines in emergence as planting depth increased were detected in sand 7 days after planting (P<0.05), but not after 14 and 21 days. Results of the study indicated that planting depth is less of a factor than seed size and soil texture in affecting emergence.